Process of producing tanning extracts.



erusnrrn GVIANOLI, or MILAN, ITnLY, Assrenon TO THE FIRM or LEPETIT,DOLLFUS Y AND GAN'SSEB, or MILAN, ITALY.

PROCESS OF PRODUCINGITANNIN EXTRACTs.

1N0 Drawing.

, Specification of Iietters Patent.

My invention relates to tanningextracts and processes of producing thesame and has particular reference to quebracho and simllar extracts ofthe character referred to in the U. S. Patent, No. 799,246, granted toLepetit and Tagliani, September 12, 1905,

such extracts inthe crude condition having the. tanning principleina-difiicultly soluble resinous condition. y

The object of the invention isto render quebracho and similarextracts'soluble, even in cold water, to convert the b ectionabIe,

insolubl'e resinous substance into such condition that it remainssoluble in the presence of the soluble part of the ext-ractand thus tomake the extract more suitable, eflicient and valuable for tanningpurposes. J Tanning materials of the character mentioned, pare ticularlyquebra'cho, while known tofpossess a large proportion of valuabletanning prin-J ciples, have'not been favorably received in the'art byreason of the said-insoluble resinous substances associated therewith;and

so far as Iam aware the process for treating them disclosed in U. Patent799,246 is' theonly one whichhas metwith practical success. Inexperimenting with such ex-v tracts, I have discovered thatlignosulfonates v of sodacont'aini'ng combined sulfurhave the property,when suitably treated, of convert- 40 ing the resinousinsolublequebra'cho extract- 1nto a readily soluble condition. Forthe purposes ofthis invention, the lignosulfonate of soda maybe obtained from wastesulfiteliquors resulting from cellulose ex- 'itraction of pulp-makingprocesses for paper,

etc;, by subjecting such liquors 'to suitable treatment to eliminate thelime and the sill I fites present therein. It may be stated that theactive constituent of these waste sulfite liquors is known as lignoresinor lignosu1- fonate, and being of the nature of an acid substance, iscapable of forming salts '.W1th alkalis-soda, lime or the like. Theproduct of the treatment results in the production of the lignosulfonateof soda, where soda is the alkali employed, as above mentioned. Thissubstance may also be termed a sodium salt of lignoresin. To free such-liquors from lime and sulfites, I add lime water to the liquor insuflicientquantity to neutralize the acid so that the'bi-sulfite of limeis converted into the insoluble neutral sulfite, which precipitatesandwhich isthen'removed in any convenient manner, as by filtration. Thesmall excess of lime is then removed by precipitation by adding asuitable proportion of soda, or of thejcheaper v Patented June 3,1913;Application filed June 30, 1908. SeriaI No. 441,205.

sulfate of soda, which causes the lime to be precipitated. compound maythen be removed in any convenient manner, as by filtration. The liquorthus treated is neutral and free from lime and sulfurous acid; itcontains principally 'llgnosulfonate-of soda and gives off no sulfurousacid, or at most only traces of it, upon addition of mineral acids. Thesul- The precipitated calcium' fite liquor, treated as abovedescribed tofree 7 the same from acid and lime, is mixed with crude resinousquebracho extract and this mixture, (the solubility ofwhich is only veryslightly increased as compared with the crude quebracl o extract,),-isheated to a temperature of from degrees to 115 -de-- grees C. for acertain period. I have found that the proportions of from 20% to 60% ofthelignosul-fonate of sodium solution after having been freed from limeand $111 furous-acid added to the crude quebraeho extract givessatisfactory results; but ohviously the proportions will be variedanddetermined according to the circumstances and the character of theextract and sul- The result of this treatment produces an extract whichis readily soluble in watera very interesting fite liquor employed.

result whichwas not at all to be expected.

As an illustrative example of thecarrying' out of the invention I givethe following:

Two thousand pounds of'crude quebracho extract bf 28 degrees B. densityis charged into a suitable vessel, capable of'be'ing heatloo ed by steamor otherwise, and provided,

preferably, with a mechanical stirring apparatus. This extract isheatedto a temperature of from 60 to, 70degrees G. in or- .der to makeit more fluid. To; this is then added about 500 'pounds of the above mentioned lignosulfonate of soda solution 10f about 25 degrees 'B.

. contain a certain amount of stirring and heating the mass for a periodof from four to five hours at a temperature of from 95 to 100 degrees0., until a test shows a sufficient degree of solubility of the .extractin cold water, as compared with the crude extract.

in an open vessel for a to five hours the mixbe heated in a closedvessel, permitting the temperature to be raised to 115 degrees 0., oreven higher. By proceeding in this manner, a comparatively short time isrequired for the rocess, the same degree of solubility being 0 tained inhalf the time, or less. The extract so obtained differs from thatobtained according to U. S. Patent 799,246, in that it does not containbi-sulfite or sulfite, although it does combined sulfur from thelignosulfonate; and the addition of bi-sulfite or acid to the hereindescribed extract or product does not alter the solubility. The productso obtained, consisting of quebracho treated with thesodiumlignosulfonate as described, has very valu- Instead of heatingperiod of from four ture may, if desired,

. able and eflicient tanning properties and I such liquors produces anice light-colored leather, particularly when treated with sulfurousacid to bleach the same to a certain extent, Such subsequent treatmentwith sulfurous' acid is merely additional and for the'purpose of 'makingthe extract more suitable or improving its condition for tanningsurfaces.

I am aware that waste residual liquors from the manufacture of sulfitepulp have but these the manner herein set forth. Patents have beengranted in Germany, andelsewhere to Mitcherlich, for the use of suchliquors for tanning purposes, but so far as I am aware such patentedprocesses have not provedwholly satisfactory or advanta eous inpractice,'for the reason that even a ter treatment of the liquors toeliminate-lime salts, etc., have not sufiicient tanning to theextraction of treatin lime compounds,

properties to be of practical commercial use.

I am also aware o the German patents, Nos. 152,236 and'195,64;3,'grantedto Max Honig andW. H. Philippi. Such processes are not whollyadvantageous or satisfactory from the presence of the lime saltsremaining in the liquor, which is very objectionable tanning materials,as also in tanning process itself In the Philippi process the'limesalts, lime of the liquors, are precipitated by means of soda, and thetreated liquor, therefore, still contains a considerable amount ofsulfurous acid in the form of sodium sulfite. According to the processof my invention,'I eliminate both the sulfurous acid and the lime.

What I claim is 1. The process of producing a soluble quebracho tanningextract which consists of treating crude: resinous quebracho extractwith lignosulfonate of soda solution at a temperature of from 95 degreesto 115 degrees C. T H

2. The process of producing soluble queb'racho tanning extracts whichconsists in crude uebracho extract with waste liquor om sul te pulpmaking, said liquor being freed from sulfurous acid and lime compounds,and conducting ,such treatment at a temperature of from 95 to 115. C.

3. The process ofiproducinga soluble quebracho tanning extract whichconsists 1n treating waste liquor from sulfite pulp making with limewater to free said liquor from sulfurous acid, then treating said liquorwith sulfate of soda to free the same from and heating the liquor sotreatedwith crude resinous quebracho extract to a temperature of fromdegrees to degrees C. I

I GIUSEPPE GIANOLI. V Witnesses:

MICHAEL SIERSLAKA, JR.,

Rnnnn'm TmPE'n'L'

